2273.     MICHEL, A., AND GALLISSOT, M.  [Thermomagnetic Anomaly at Ordinary Temperatures in Microcrystalline Ferromagnetic Substances.]  Compt. rend., vol. 207, 1938, pp. 140-142; Chem. Abs., vol. 32, 1938, p. 6919.

        Cause of the anomaly in the magnetization; temperature curves of various ferromagnetic substances, Fe₂O₃ and various ferrites, according tot he state of crystallization, are discussed, and the explanation is suggested that the Curie points of the minute crystallites in the microcrystalline varieties vary, being lower the smaller the crystallite, but always above 20°, below which the normal law is followed.  Thus a hyperbolic form of curve may be due to physical as well as chemical heterogeneity.